ESCR - Marlbank-Cuilcagh Mountain Region; Tullyhona, Brookfield and Trien

Earth Science Conservation Review

Summary Full report
Marlbank-Cuilcagh Mountain Region; Tullyhona, Brookfield and Trien	Fermanagh

Site number:	1154
ESCC:	IC
Locality Type:	Karst	Status:	ASSI
Grid Reference:	H1533 Approximate
Google maps:	54.24613,-7.76988
County:	Fermanagh	Council area:	Fermanagh & Omagh District Council
Period:	Quaternary, Carboniferous
Stages:	Asbian, Holocene, Visean
Lithostrat:	Dartry Limestone Formation, Glenade Sandstone Formation, Glencar Limestone Formation, Knockmore Limestone Member

Site Description
Surface karst: Tullyhona Knoll.
Highlights:
Tullyhona Rising Cave is a dendritic river cave system completely formed within one carbonate mudbank "stack". Features present within the system include well developed speleothems, perched active sumps, fracture and bedding passage control, partial dolomitization along faults, roof collapse along shale bands and abandoned stream passages. The cave and surface karst are, at present, in a very good state of preservation.
Introduction:
The Tullyhona Karst is located within parts of Brookfield, Tullyhona, Trien and Deer Park townlands, located at the eastern end of the Marlbank area. Topography is dominated by carbonate mudbank "knoll" topography. The area hosts one major cave system, Tullyhona Rising Cave, and its associated sites. There are a number of minor speleological sites which may be associated with Tullyhona Rising Cave. Surface karst features, such as dolines, sinks and karren, are well developed. The area totals approximately 1.25 sq km. History of Exploration: The entrance squeeze was passed by the CPC, and later a combined CPG-ISA group in the summer of 1968. The Farr Country, Up The Junction and Oxbow Inlet were discovered in 1972 by M. Farr (CDG) who successfully passed the sump by diving. The dry bypass (Fenian Terror Bypass) to the sump was discovered by the Reyfad Group in 1974, the initial attempt by E. Devoy having failed, it was subsequently passed by G. Ll. Jones and H. Ball. Major speleological sites: Tullyhona Rising Cave (H1533 3373) (1500m+ long, 65m deep), Dick's Sinks (H1503 3335), Whiskey Holes (H1545 3332) and (H1554 3332). Minor speleological sites: Tullyhona Rock Pots (H152 333), Brookfield Sink No.1 (H1458 3339). Total surveyed cave: 1500m+. Area of exposed limestone pavement: ~400m2. Catchment area: 1.5-2km2.
Description:
I - Hydrology The main point input to Tullyhona Rising Cave is derived from two streams draining the northern slopes of Trien Mountain. These streams sink in two distinct groups of sinkholes; Dick's Sinks to the east which feed the stream in Up The Junction Passage and Whiskey Holes to the west which feed the stream in Oxbow Inlet Series. Several small inlets are encountered in the cave and these may represent small autogenic streams on the surface or accumulated allogenic input. The two streams meet at the Junction to form the Main Stream which resurges at Tullyhona Rising. II - Underground Karst The main underground karst feature in the Tullyhona area is Tullyhona Rising Cave. Tullyhona Rising and the cave entrance are located at the head of a small stream which rises at the Glencar - Dartry Limestone contact in Tullyhona townland. The main streams feeding the stream in Tullyhona Rising Cave sink at Dick's Sinks and Whiskey Holes. Surface karst: Whiskey Holes. The stream from Dick's Sinks enters Tullyhona Cave through a series of tributaries in the area of Shatter Chamber at the upstream end of Up The Junction. The stream flows through approximately 250m of joint controlled passage with extensive coarse (sand - gravel) active clastic deposits forming the floor of the passage. Calcite speleothems are rare. The stream sinking at Whiskey Holes enters the cave at the upstream end of Oxbow Inlet and follows approximately 150m of predominantly joint controlled passage. The Whiskey Holes and Dick's Sink streams meet underground at the Junction. From the Junction the stream flows through The Farr Country, 150m of magnificent passage consisting of 5m square passage with a number of larger chambers and a 25m long duck towards the upstream end of the passage. At the end of The Farr Country the passage trends sharply E-W. The stream flows north after 25m, cutting down to Sump 1. The E-W passage continues at high level to Crystal Crunch, a 2m wide phreatic tube with a wide vadose slot in the floor of the passage. Tullyhona Rising Cave: the Crystal Crunch, showing fossil phreatic passage with fossil vadose trench. Tullyhona Rising Cave: entrance to the Crystal Crunch from the Farr Country. Gour pools, flowstone and cave pearls are well developed in the floor of this passage. Tullyhona Rising Cave: the Crystal Crunch. Tullyhona Rising Cave: gour pools in the Crystal Crunch. Tullyhona Rising Cave: pool deposits (shelfstone) in the Crystal Crunch. Tullyhona Rising Cave: the Crystal Crunch. Sump 1 is 3.5m deep and 9m long and forms a U-bend in section. The stream emerges from Sump 1 at the head of a 4m high waterfall, forming a perched sump. Tullyhona Rising Cave: waterfall from the perched Sump 1. At the end of Crystal Crunch a 2m climb leads to Fenian Terror Bypass, a high narrow rift with many sharp projections on the passage walls. At the end of this passage the main stream in Tullyhona 1 is reached, Tullyhona Rising Cave: Main Stream Passage, Tullyhona 1. Tullyhona Rising Cave: Main Stream Passage, Tullyhona 1. Crystal Crunch and Fenian Terror forming a dry bypass to Sump 1. From the Fenian Terror - stream passage junction, the stream flows through a series of strongly joint controlled passages, initially with deep water and then steeply descending vadose passages with a number of cascades. There are no clastic sediments in this area of the cave. The passage shape changes dramatically at The Ducks, becoming wide and low, rather than high and narrow. Tullyhona Rising Cave: ducks in the entrance series. After The Ducks is the Boulder Chamber, a wide 2m high chamber with a shale band exposed in the roof and with abundant breakdown. From the Boulder Chamber the stream passage consists of approximately 2m by 2m passages with abundant breakdown blocks of mudbank limestones obstructing the passage. Close to the cave entrance the passage exposes the Dartry Limestone - Glencar Limestone contact in the passage floor. Tullyhona Rising Cave: passage just upstream of the entrance squeeze showing the Dartry/Glencar Limestone contact. The initial entrance squeeze is a very tight passage formed within the upper 1m of the Glencar Limestone. Tullyhona Rising Cave: entrance squeeze. 5m downstream of the entrance squeeze is Tullyhona Rising. Calcite speleothems are particularly abundant in The Farr Country but are rare in Tullyhona 1, Up The Junction and the Oxbow Inlet. Coarse clastic stream deposits are well developed in Up The Junction and The Oxbow Inlet. Tullyhona Rising Cave: speleothems in the Farr Country. Tullyhona Rising Cave: flowstone in the Farr Country. Tullyhona Rising Cave: speleothems in the Farr Country. Tullyhona Rising Cave: shield formation in the Farr Country. Tullyhona Rising Cave: speleothems in the Farr Country. Tullyhona Rising Cave: speleothems in the Farr Country. Tullyhona Rising Cave: speleothems in the Farr Country. Tullyhona Rising Cave: speleothems in the Farr Country. III - Surface karst Limestone pavement is well developed on the surface of the limestone knolls formed by the carbonate mudbank topography. Surface karst: frost shattered scree, Tullyhona Knoll. Sinkholes are well developed in the southwest of Tullyhona townland and solution dolines and small pots are common in the eastern Brookfield area Surface karst: Brookfield Sinks. and along the limestone bench south of the limestone scarp which forms the boundary between Trien and Deer Park townlands.
Importance:
The Tullyhona Karst and its associated surface and underground features are, at present, in a very good state of preservation. The cave system illustrates many classic features of speleogenesis including joint and fracture control, shale bed control, vadose downcutting, stream diversion and passage abandonment (probably due to valley floor deepening) and differential solution associated with dolomitization along faults. Calcite speleothems are particularly well developed in the Farr Country. The perched sump is one of the few, and best, examples of this feature in Northern Ireland.
Interpretation:
I - Hydrology The hydrology of the Tullyhona area appears to be relatively simple, with larger streams sinking into larger sinkholes, with diffuse input from solution doline areas. All the water which sinks in the area resurges at Tullyhona Rising. A permanent surface stream immediately east of and below Dick's Sinks has a small rising approximately 30m from Dick's Sinks and this may indicate partial capture of the stream sinking at Dick's Sinks by the permanent surface stream. II - Underground Karst Tullyhona Rising Cave is a dendritic vadose cave developed within carbonate mudbanks of the Knockmore Limestone Member. Sink location is controlled by the fault contact between the Glenade Sandstone and Dartry Limestone Formations. The resurgence level is controlled by the Dartry - Glencar Limestone Formation contact. The initial inlet passages, Up The Junction and the Oxbow Inlet are joint controlled vadose passages with abundant clastic deposits derived from the surface streams. After these streams join, the passage increases in size probably due to increased flow in this section of cave. The significant change in passage direction at the end of the Farr Country occurs where a major E-W oriented fault or joint is reached by the stream. This E-W oriented passage (Crystal Crunch) and Fenian Terror Bypass are probably the original route taken by the stream, the N-S oriented passage through Sump 1 having captured the stream as it cut down, leaving Crystal Crunch and Fenian Terror abandoned. Tullyhona Rising Cave: the Crystal Crunch, showing fossil phreatic passage with fossil vadose trench. This stream capture by the N-S oriented passage may be related to deepening of the MacNean valley. Fenian Terror Bypass is formed along a minor fault; the many sharp projections on the passage wall are due to dolomitization of micrites in the mudbank limestones, differential solution of the dolomites and the calcite spar cements in the mudbanks leaving the dolomites standing proud. The perched Sump 1 and the waterfall also show dolomite projections and Fenian Terror and the waterfall appear to be controlled by parallel fractures. From the waterfall the stream passage cuts rapidly down a joint controlled passage to The Ducks and the Boulder Chamber where a thick shale band has controlled passage form and led to extensive roof breakdown. The following passages are formed within the Dartry Limestone immediately above the Glencar - Dartry Limestone contact and thin shales within the carbonate mudbanks have allowed extensive breakdown of mudbank limestones to take place. At the entrance the passages are restricted and low, reflecting the control exerted on passage form by the thinly bedded limestones and shales of the upper Glencar Limestone. III - Surface Karst Surface karst in the Tullyhona Area is predominantly composed of sinkholes, dolines and karren developed on a post-glacial topography, which reflects the original topography of the carbonate mudbanks of the Knockmore Limestone Member. Surface karst: frost shattered scree, Tullyhona Knoll.
Conclusions:
Tullyhona Rising Cave is an excellent example of a vadose dendritic river cave developed within carbonate mudbanks in the Dartry Limestone. The cave system illustrates many classic features of speleogenesis. The arduous nature of the passages leading to the well decorated portion of the cave (Farr Country) and the frequency and intensity of flooding in the cave passages downstream of the sump have resulted in a high state of preservation within this cave.
Notes:
For site specific information see; Key Site 334 - Tullyhona Rising Cave Key Site 335 - Dick's Sinks Key Site 336 - Whiskey Holes Key Site 337 - Tullyhona Rock Pots Key Site 338 - Brookfield Sink No. 1. For information and reference lists on the systems and features of other karst areas within the Marlbank-Cuilcagh Mountain Region see; Key Site 1153 - East Cuilcagh Key Site 1155 - Prod's Pot - Cascades Rising Area Key Site 1156 - Marble Arch Karst Key Site 1157 - Western Marlbank. BIOLOGICAL INTEREST No fauna has been previously recorded from this site and no collection was made in the course of the current programme.

Keywords
Minerals:	Calcite, Dolomite, Micrite, Sparrite
Rocks:	Limestone, Shale
Structures:	bedding, fault, joints
Geomorph:	breakdown, cave, cave pearls, dendritic river cave, doline, flowstone, gour pool, helictite, karren, limestone pavement, sinkhole, stalactite, stalagmite, straw, sump

Access
Planning:	HISTORY OF EXPLORATION The entrance squeeze was passed by the CPC, and later a combined CPG-ISA group in the summer of 1968. The Farr Country, Up The Junction and Oxbow Inlet were discovered in 1972 by M. Farr (CDG) who successfully passed the sump by diving. The dry bypass (Fenian Terror Bypass) to the sump was discovered by the Reyfad Group in 1974, the initial attempt by E. Devoy having failed, it was subsequently passed by G. Ll. Jones and H. Ball.
Management:
Approach to the entrance of Tullyhona Rising Cave is normally made through land owned by the Department of Agriculture N.I. (Forestry Service). The entrance to the cave, and the cave system itself, lies on, and under, private land. The cave is suitable for visits by experienced cavers only and is not used by educational etc. groups. Internal Threats: Tullyhona Rising Cave consists mainly of active river passages. The passages from the entrance to the downstream end of Fenian Terror Bypass are devoid of calcite speleothems and are high energy, being prone to extreme flooding. The Bypass and the passage immediately at the end contain no significant deposits and damage is unlikely to this point. The floor of Crystal Crunch, however, is completely covered in well developed gour pools and other calcite speleothems which can be avoided by walking with one foot on each ledge either side of the passage. Tullyhona Rising Cave: the Crystal Crunch. This area could suffer damage if this technique is not followed by all cavers passing this section of passage. The Farr Country is an active stream passage which is sometimes low (~1.5m) and has many fine formations, some of which could be accidentally damaged by passing cavers. The Oxbow Inlet and Up The Junction are low stream passages with no calcite speleothems and extensive active sand and gravel banks which cannot be permanently damaged by passing cavers. External threats: The surface karst is, at present, in a good state of preservation. There are a number of animal pens adjacent to the stream feeding Dick's Sinks and some pollution from this source is evident in the water quality in the cave. Some dumping has occurred in the past but has not been noticed recently.
Threats:	Accidental damage by passing cavers; pollutants from animal pens adjacent to streams feeding sinks.
Uses
Potential:	It would be a relatively simple exercise to connect to the cave via Dick's Sinks or Whiskey Holes to enable a sink to rising through trip. This would inevitably lead to an increase in traffic through the cave. Further research on many aspects of the karst in this area would enhance understanding of the geomorphological evolution of the area.

References (28)
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Map(s):	Two areas have been defined on 1:10,000 sheet 243; T1. Covers the known cave passages in Tullyhona Rising Cave. T2. Covers the known karst catchment for Tullyhona Rising Cave and an area of well exposed karren in Brookfield townland.
Record type:	ESCR report
Entered by:	E M Porter
Last updated:	13 Apr 2004

Enlander, I., Dempster, M. & Doughty, P., 2026. Marlbank-Cuilcagh Mountain Region; Tullyhona, Brookfield and Trien, County Fermanagh, site details. [In] Earth Science Conservation Review.
https://www.habitas.org.uk/escr/site.php?item=1154. Accessed on 2026-11-06.